Prosthesis used for joining and replacing human bones and joints necessitate a means for conveniently and reliably locking bones and joints securely together in an articulating or a nonarticulating manner. Various conventional mechanical locking devices, such as screw threads and collets, have been used, but they have the problem of releasing or backing off under prolonged service or might not be convenient for installation and removal in surgery. An object of this invention is to provide a simple and economical prosthesis for locking joints and bones together, and more particularly, to such a prosthesis which facilitates the installation and removal of articulating prosthetic joints in the human body.